For the Abbott government, Manus is a literal and political nightmare, as immigration minister Scott Morrison admitted he was unable to guarantee that there wouldn’t be further disturbances.

Other countries, with much more serious pressures from asylum seekers, might wonder how Australia’s outsourced “PNG solution” has come to this. But there was an inevitability about it when detainees live in distressing conditions with no clarity about their future.

Morrison’s answer – that they should not have got on boats – is beside the point.

Following the second consecutive night of violence, this one with a fatality, Tony Abbott spoke with his Papua New Guinea counterpart, Peter O’Neill.

A drawing by child refugees on Manus Island.

No doubt to his considerable relief, Abbott received assurances that PNG remains committed to the Manus detention centre and to resettling in that country asylum seekers found to be refugees. If PNG tried to go back on its deal, the Australian government would have more trouble.

In the wake of the violence, Abbott also called a meeting in Canberra of cabinet’s national security committee and the government put 100 security personnel on standby.

At morning and evening news conferences, Immigration minister Scott Morrison looked a little shaken but retained some of his usual defiance. Tensions had been there, he said; such a situation had been anticipated, security had recently been strengthened.

People would seek to tear detention centres down; they would make wild allegations, Morrison said. He highlighted that “despite what is a terrible tragedy, the centre stands, the centre operates and the centre was operating first thing this morning.” Breakfast had been served.

The whole thing was cast as another front in the government’s border security war.

So far, a lot of detail is missing about what happened on Monday night. The Iranian died from head injuries but Morrison could not say how or where they were inflicted. Shots were fired by the PNG police, but the circumstances aren’t known.

Nor is there any information about how another asylum seeker was shot in the buttocks. Morrison rejected unverified claims that outsiders had attacked the centre and the asylum seekers, but could not be sure people from outside hadn’t gone in.

The UN refugee agency, UNHCR visited Manus in October and its report paints a graphic picture of the harsh physical conditions and the detainees’ mood, including their fears about safety following a clash between PNG police and military outside the centre.

A map showing Manus Island’s location.

The report said bluntly that the PNG practice of detaining all asylum seekers at the closed centre “on a mandatory and open-ended basis, without an individualised assessment as to the necessity, reasonableness and proportionality of the purpose of such detention, amounts to arbitrary detention that is inconsistent with international law”.

It also pointed out that Australia’s responsibilities under international instruments to which it is party “remain engaged and cannot be extinguished by the physical transfer of asylum seekers to PNG”.

The UNHCR made one very key point among many findings and recommendations – and this would surely seem to go to the nub of what the Australian government should be doing.

“UNHCR’s view is that reasonable and appropriate time frames should be implemented and communicated to asylum seekers. This is integral not only for a fair and efficient asylum system, but also for the psycho-social well-being of asylum seekers.”

Uncertainty can be deeply debilitating for people in quite ordinary circumstances, let alone for those who have often been through traumatic experiences and are now locked up in bad conditions.

Setting, in conjunction with PNG, timetables for processing the more than 1300 people on Manus would not be a softening of policy (which the government is determined to avoid at all costs). It would the humane, decent and competent way to proceed.

The processing is done by PNG with Australian mentoring. Somehow Australia has to find a way to have it done more expeditiously. So far, not one person has been found to be a refugee, and Morrison did not think anyone at all had been fully processed.

Asked whether he had a date or a time in his mind for having Manus empty, Morrison said he was “not about to make any sort of speculative forecasts”.

The boats appear to have stopped, with no arrivals for two months. This gives the opportunity to tackle the Manus issue, because it would not be exacerbated by new arrivals. The qualification is that Morrison is threatening to send more people there from Christmas Island.

The UN Refugee agency says the detention of refugees on Manus Island breaks international law.

Forcing the pace of processing would be a start to dealing with the Manus problem, although it would then bring other difficulties including repatriating reluctant people whose claims failed.

The government is determined, as part of its deterrent, to insist that those found to be refugees must be settled in PNG and PNG only. This is something the UNHCR is “very concerned by”. It said in its report that from its nearly 30 years of firsthand experience in the country “it is clear that sustainable integration of non-Melanesian refugees in the socio-economic and cultural life of PNG will raise formidable challenges and protection concerns”.

For people granted asylum on the basis of a genuine fear of persecution in their home country to then need protection from the citizens of their new one would be a cruel twist indeed.

Michelle Grattan does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.